OT2 Extra Battles - True Vide, the Wicked Superboss (LV99)

This is probably the hardest fight in all of Octopath. Even my overgrinded save file got hit very hard.

This video doesn't really serve as a guide since I relied a lot on luck and my Ochette with 999 in every stat (they told me nut grinding would be pointless, ha!) isn't feasible by normal players, same as everyone having a Battle-tested Shield.

I included my gear and passives nontheless.

The only advice I can give for this is to use Supreme Luck of the Cait from Chubby Cait. Just spam it whenever you can. It massively boosts survival chance and can even revive party members in a pinch. Also use Foreign Assassins on as many characters as you can fit, they are probably the best source of healing you will find anywhere.

A very valuable thing to know is that the Celestial Intervention effect (The one that negates all buffs) can be cleared by Chubby Cait's Opulent Restorative. This means if you get lucky you can still get your important boosts from Opulent Trio or Lap of Luxury.

In the final phase, Vide will be extremely hard to break and is guaranteed to heal 800,000 HP, giving it an effective 1,8 million HP. With its four actions per turn and all the bs it throws at you, it's better to get it as low as possible in one break and then finish it off the turn after.